Remove legacy tests

Shell transitions has landed and it's the only system we run in master

Bug: 217777115
Bug: 197726610
Bug: 246284124
Bug: 240918620
Fixes: 273944864
Test: atest FlickerTests WMShellFlickerTests
Change-Id: I89755ca76b9fb11a079755213f7f9e60749b79ab